Pneumatic door-check



(No Model.)

G. S. PERKINS.

' PNEUMATIODOOR CHECK.

vN0. 294,905. Patented Mar. 11, 1884.

2W 3 a 0-0, I Z;

N. PETERS. Phnlwlilhngnpher. Washington. 0.x;

UNITED STATES GUSTAVUS S. PERKINS, OF

PATENT Er ca.

HARTFORD, CONNECTICUT.

PNEUMATIC DOOR-CHECK.

SPECIFICATION forming part of Letters Patent No. 294,905, dated March11, 1884. I

a Application filed August 21, 1882. (No model.)

To all; whom it may concern.-

Be it known that I, GUSTAVUS S. PERKINS, of Hartford, in the county ofHartford and State of Connecticut, have invented a certain new anduseful Improvement in Door-Checks, of whichthe following is adescription, reference being had to the accompanying drawv ings, whereFigure 1 is a top view of my device as ap plied to a door. Fig. 2 is aview of same in longitudinal central section, showing the door open.Fig. 3 is a detail view of one end of the cylinder, the thumb-nut andwasher removed to show the adj ustable vent.

My invention relates to the class of devices for preventing theslammingof doors by the use of an-air-cushion, and known as pneumaticdoor-checks.

The invention consists in the new and improved combination of partsthat'renders the pressure of the spring practically uniform, whether thedoor is open or shut, gives a compact arrangement of operating parts,and renders the adjustable vent of the air-chamber easily accessiblewhen the door is closed.

In the accompanying drawings, the letter a denotes a cylinder,preferably of metal, as brass. 1) denotes a piston, usuallyleather-packed, and so fitted to the cylinder as to be air-tight; c, apiston-rod fast to the piston at one end,vand pivoted to the standard d,appurtenant to plate 6, at the other. The cap f is recessed, as shown inFig. 2, so that the cylinder fits closely upon the plate 6, to which ispivoted the guide-rods g, which are pivoted at their outer end to thecap h of the cylinder. To the same cap, h, is pivoted the lever-arm c,which is also pivoted to the stand or bracket 70, adapted to be securedto a door. The cap h is ordinarily fastened to the cylinder by ascrew-thread, and holds between them a leather disk, Z, slitted for theadmission of air to the cylinder,

- as through the opening 7r, when the piston is drawn outward. Anotheropening, if, is provided in cap h, closed by a thumb-nut, m, and thislatter opening is used to adjust the outflow of air under pressure ofthe piston, which is impelled in closing the door by a coiled spring, a,arranged within the cylinder about the rod, and bearing upon the cap andback of the piston. I

My device is readily applicable to either a right or left hand door,with no change in the parts herein shown, the plate e being fastened tothe jamb over the door at a point near the hinge side, and the stand orbracket in to the upper edge of the door at a point farther removed fromthe hinge side.

By means of dotted lines in Figs. 1 and 2, I have illustrated theoperation of the device considered as a lever, the spring being thepower applied between the pivot e on the plate 0 and the pivot k on thebracket k. The short arm of the lever, from eto 9:, remains almostconstant, as the door is swung open, while the longer arm increasesrapidly in length as the door is opened, as illustrated in Fig. 2, andthe weight and friction of the door upon its hinges is also constant. Atthe same time the compression and resiliency of the coiled spring haveincreased,with the result of a practicallyuniform pressure upon the doorat all points of its path between the extremes of open and shut-adesirable feature in many places.

- By arranging the cylinder in the manner shown, the air-ch amber andits openings to the outer air are located on the outer end of thecylinder, with the adjustable vent covered by the thumb-nut in aposition easy of access.

I am aware that pneumatic door-checks consisting of the combination ofthe aircylinder, levers, and brackets, and also having adjustable ventsfor governing the speed and force of closing the door, are not new, andthese I do not .broadly claim.

Iclaim as my invention 1-. I11 a pneumatic door-check, a cylinder, a,pivotally connected to guide-rods g, lever z, and bracket k, incombination with piston Z1, spring a, and rod 0, pivoted to stand e,whereby the'cylinder is reciprocated'on the piston in opening andclosing the door, all substantially as described, and for the purposeset forth.

2. In a pneumatic door-check, the combination of the cylinder a, havingrecessed head f and cap 71, with vent 7L2 and adjustable thumbnut m,piston b, rod 0, plate 6, having standard d, guide-rods g, lever 75, andbracket 7:, all substantially as described.

GUSTAVUS S. PERKINS.

W'itnesses:

O. L. BURDETTE, U. H. MARsH.

